Package structure of micro-electro-mechanical-system microphone package and method for packaging the same
A package structure of MEMS microphone is provided. The MEMS microphone includes a MEMS microphone chip disposed on a circuit board. The MEMS microphone chip comprises a first bonding pad, including a metal pad on a top of the MEMS microphone chip; and a protection layer fully enclosing a sidewall of the metal pad and also partially disposed on a top of the metal pad. A circuit chip is disposed on the circuit board, wherein the circuit chip comprises a second bonding pad. A bonding wire is connected between the first bonding pad and the second bonding pad.
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The invention is related to MEMS (Micro Electro Mechanical System) microphone package technology, and particularly related to the package structure of MEMS microphone and the method for packaging the same.
2. Description of Related ArtMicrophone has been designed based on semiconductor fabrication technology, so as to greatly reduce the size. The MEMS microphone is a popular device used in electronic apparatus to sense acoustic signals, such as the communication voice.
After the MEMS microphone chips are fabricated on a wafer and cut into multiple chips, the MEMS microphone in single chip is connected to an integrated circuit, such as an application-specific integrated circuit (ASIC), by packaging process.
As to the packaging process, once the MEMS microphone chip and the ASIC chip are separately fabricated, they are disposed on a circuit board. Then, the wire bonding process is performed to connected together to form a MEMS microphone for adapting into various applications. Actually, each of the MEMS microphone chip and the ASIC chip has bonding pads. The wire bonding process are bonding between the bonding pads of the MEMS microphone chip and the ASIC chip.
However, due to usual fabrication manner as taken to fabricate the MEMS microphone chip, material of the bonding pads of the MEMS microphone chip is based on aluminum. Then, the aluminum bonding pad may be suffer corrosion, resulting in damage.
How to package the MEMS microphone to effectively avoid the corrosion on the bonding pad of the MEMS microphone chip is an issue in the packaging process.
SUMMARY OF THE INVENTIONThe invention provides a package structure of MEMS microphone and the packaging method thereof. The bonding pad of the MEMS microphone may be well protected to reduce the corrosion of the bonding pad.
In an embodiment, the invention provides a package structure of MEMS microphone. The MEMS microphone includes a MEMS microphone chip disposed on a circuit board. The MEMS microphone chip comprises a first bonding pad, including a metal pad on a top of the MEMS microphone chip; and a protection layer fully enclosing a sidewall of the metal pad and also partially disposed on a top of the metal pad. A circuit chip is disposed on the circuit board, wherein the circuit chip comprises a second bonding pad. A bonding wire is connected between the first bonding pad and the second bonding pad.
In an embodiment, the invention provides a package structure of MEMS microphone, comprising a MEMS microphone chip, disposed on a circuit board, wherein the MEMS microphone chip comprises a first bonding pad, the first bonding pad is located on a top of the MEMS microphone chip. A circuit chip is disposed on the circuit board, wherein the circuit chip comprises a second bonding pad. A bonding wire is connected between the first bonding pad and the second bonding pad. A sealant structure is locally covering on the first bonding pad and an end portion of the bonding wire on the first bonding pad.
In an embodiment, the invention provides a method for packaging MEMS microphone, comprising: providing a circuit board, a MEMS microphone chip and a circuit chip, wherein the MEMS microphone chip comprises a first bonding pad, the circuit chip comprises a second bonding pad. The first bonding pad comprises: a metal pad on a top of the MEMS microphone chip; and a protection layer fully enclosing a sidewall of the metal pad and also partially disposed on a top of the metal pad. In addition, the MEMS microphone chip and the circuit chip are disposed on the circuit board. A bonding process is performed to connect between the first bonding pad and the second bonding pad by a bonding wire.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
The invention is directed to a structure of MEMS microphone package and a method for packaging the MEMS microphone. The bonding pad of the MEMS microphone chip may be well protected from corrosion.
Several embodiments are provided for describing the invention but the invention is not limited to the embodiments as provided. Further, a proper combination between the embodiments may also be further done.
The invention has looked into the package structure of MEMS microphone, so to improve the quality of the MEMS microphone.
Referring to
The bonding pad 106 with the bonding wire 112 of the MEMS microphone chip 104 is usually exposed, in which the bonding pad 106 is aluminum pad. After then, a cap 102 covers the MEMS microphone chip 104 and the circuit chip 108 for protection.
Here, the structure of the MEMS microphone chip 104 is formed depending on the actual design without specific limitation. However, it basically includes a backplate and a diaphragm. The backplate has venting holes to pass the acoustic signal and also aha the electrode structure. The diaphragm receives the acoustic signal and vibrate correspondingly, so to change the capacitance level with the acoustic frequency. The circuit in the backplate converts the capacitance effect into electric signals to the circuit chip 108 for subsequent application.
A cross-sectional structure of the boding pad 106 is shown at the lower part of
After looking into the metal pad 136 described above, the invention in an embodiment has proposed some embodiments to effectively protect the metal pad.
Referring to
In another embodiment, the conductive protection layer 200 may be modified.
For the general protection layer on the metal pad 136, the conductive protection layer 200 is at least disposed on top of the metal pad 136. The sidewall of the metal pad 136 may be covered by the same conductive layer 200 in
To the conductive layer 200, it may also be further modified in an embodiment.
Multiple embodiment to form the metal pad 136 are also provided.
Referring to
In an embodiment, the conductive protection layer 200 may be further modified.
Referring to
The structure in
As noted in referring to
In a further embodiment,
Referring to
Usually, the circuit chip 300 is a bulk structure and the glob top 304 for sealing in a large area is easily applied on the top to have fully protection on the circuit chip 300. However, the MEMS microphone chip 108 including the diaphragm 120 in the conventional manner is not applied with the glob top structure. As looking into
As to the foregoing descriptions, the invention in embodiments may be generally stated as follows.
In an embodiment, the invention provides a package structure of MEMS microphone. The MEMS microphone includes a MEMS microphone chip disposed on a circuit board. The MEMS microphone chip comprises a first bonding pad, including a metal pad on a top of the MEMS microphone chip; and a protection layer fully enclosing a sidewall of the metal pad and also partially disposed on a top of the metal pad. A circuit chip is disposed on the circuit board, wherein the circuit chip comprises a second bonding pad. A bonding wire is connected between the first bonding pad and the second bonding pad.
In an embodiment, as to the package structure, the metal pad contains aluminum and the protection layer contains TiN.
In an embodiment, as to the package structure, the protection layer provides a barrier capability from corrosion of the metal pad.
In an embodiment, as to the package structure, the MEMS microphone chip comprise: a silicon substrate; a MEMS structure, disposed on the silicon substrate; a circuit layer, disposed on the silicon substrate, the circuit layer connected to the MEMS structure; and the first boding pad, disposed on the circuit layer.
In an embodiment, as to the package structure, the bonding wire is a gold wire.
In an embodiment, as to the package structure, the first boding pad comprises an anode pad and a cathode pad of the MEMS microphone chip.
In an embodiment, as to the package structure, an end portion of the bonding wire is disposed on the top of the metal pad and the protection layer comprises a conductive layer at least covering on the top of the metal pad enclosing the end portion of the bonding wire.
In an embodiment, as to the package structure, the conductive layer further comprises a portion fully enclosing the sidewall of the metal pad.
In an embodiment, as to the package structure, the protection layer further comprises a dielectric layer fully enclosing the sidewall of the metal pad.
In an embodiment, as to the package structure, the dielectric layer further covers a peripheral region of the conductive layer on the top of the of the metal pad.
In an embodiment, as to the package structure, the conductive layer contains TiN and the metal pad contains aluminum.
In an embodiment, as to the package structure, the protection layer comprises a single-layer conductive layer or a conductive layer with a glue layer on the metal pad.
In an embodiment, the invention provides a package structure of MEMS microphone, comprising a MEMS microphone chip, disposed on a circuit board, wherein the MEMS microphone chip comprises a first bonding pad, the first bonding pad is located on a top of the MEMS microphone chip. A circuit chip is disposed on the circuit board, wherein the circuit chip comprises a second bonding pad. A bonding wire is connected between the first bonding pad and the second bonding pad. A sealant structure is locally covering on the first bonding pad and an end portion of the bonding wire on the first bonding pad.
In an embodiment, as to the package structure, the bonding pad contains aluminum.
In an embodiment, as to the package structure, the sealant structure comprises a glob top structure.
In an embodiment, the invention provides a method for packaging MEMS microphone, comprising: providing a circuit board, a MEMS microphone chip and a circuit chip, wherein the MEMS microphone chip comprises a first bonding pad, the circuit chip comprises a second bonding pad. The first bonding pad comprises: a metal pad on a top of the MEMS microphone chip; and a protection layer fully enclosing a sidewall of the metal pad and also partially disposed on a top of the metal pad. In addition, the MEMS microphone chip and the circuit chip are disposed on the circuit board. A bonding process is performed to connect between the first bonding pad and the second bonding pad by a bonding wire.
In an embodiment, as to the method for packaging MEMS microphone, the metal pad contains aluminum and the protection layer contains TiN.
In an embodiment, as to the method for packaging MEMS microphone, the protection layer provides a barrier capability from corrosion of the metal pad.
In an embodiment, as to the method for packaging MEMS microphone, an end portion of the bonding wire in the bonding process is disposed on the top of the metal pad and the protection layer comprises a conductive layer at least covering on the top of the metal pad enclosing the end portion of the bonding wire.
In an embodiment, as to the method for packaging MEMS microphone, the MEMS microphone chip is provided by: forming the metal pad on the top of the MEMS microphone chip; forming a conductive layer, covering on the MEMS microphone chip and the metal pad; removing a side portion of the conductive layer. A residual portion of the conductive layer serves as the protection layer to fully cover the top and a sidewall of the metal pad. an end portion of the bonding wire in the bonding process is penetrating the protection layer and connected to the metal pad.
In an embodiment, as to the method for packaging MEMS microphone, the MEMS microphone chip is provided by: sequentially forming a metal layer and a conductive layer on the MEMS microphone chip; patterning the metal layer and the conductive layer to respectively form the metal pad and a conductive protection layer; forming a dielectric layer, fully covering over the metal pad and the protection layer; and patterning the dielectric layer to have an opening to expose the conductive protection layer. An end portion of the bonding wire in the bonding process within the opening is penetrating the conductive protection layer and connected to the metal pad. The dielectric layer with the conductive protection layer forms the protection layer on the metal pad.
In an embodiment, as to the method for packaging MEMS microphone, the conductive layer comprises a single-layer conductive layer or a conductive layer with a glue layer on the metal pad.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
Claims
1. A package structure of micro-electro-mechanical-system (MEMS) microphone, comprising:
- a MEMS microphone chip, disposed on a circuit board, wherein the MEMS microphone chip comprises a first bonding pad, the first bonding pad comprises: a metal pad on a top of the MEMS microphone chip; and a protection layer, fully enclosing a sidewall of the metal pad and also partially disposed on a top of the metal pad;
- a circuit chip, disposed on the circuit board, wherein the circuit chip comprises a second bonding pad; and
- a bonding wire, connected between the first bonding pad and the second bonding pad.
2. The package structure as recited in claim 1, wherein the metal pad contains aluminum and the protection layer contains TiN.
3. The package structure as recited in claim 1, wherein the protection layer provides a barrier capability from corrosion of the metal pad.
4. The package structure as recited in claim 1, wherein the MEMS microphone chip comprise:
- a silicon substrate;
- a MEMS structure, disposed on the silicon substrate;
- a circuit layer, disposed on the silicon substrate, the circuit layer connected to the MEMS structure; and
- the first boding pad, disposed on the circuit layer.
5. The package structure as recited in claim 1, wherein the bonding wire is a gold wire.
6. The package structure as recited in claim 1, wherein the first boding pad comprises an anode pad and a cathode pad of the MEMS microphone chip.
7. The package structure as recited in claim 1, wherein an end portion of the bonding wire is disposed on the top of the metal pad and the protection layer comprises a conductive layer at least covering on the top of the metal pad enclosing the end portion of the bonding wire.
8. The package structure as recited in claim 7, wherein the conductive layer further comprises a portion fully enclosing the sidewall of the metal pad.
9. The package structure as recited in claim 7, wherein the protection layer further comprises a dielectric layer fully enclosing the sidewall of the metal pad.
10. The package structure as recited in claim 9, wherein the dielectric layer further covers a peripheral region of the conductive layer on the top of the of the metal pad.
11. The package structure as recited in claim 7, wherein the conductive layer contains TiN and the metal pad contains aluminum.
12. The package structure as recited in claim 1, wherein the protection layer comprises a single-layer conductive layer or a conductive layer with a glue layer on the metal pad.
13. A package structure of micro-electro-mechanical-system (MEMS) microphone, comprising:
- a MEMS microphone chip, disposed on a circuit board, wherein the MEMS microphone chip comprises a first bonding pad, the first bonding pad is located on a top of the MEMS microphone chip;
- a circuit chip, disposed on the circuit board, wherein the circuit chip comprises a second bonding pad;
- a bonding wire, connected between the first bonding pad and the second bonding pad;
- a sealant structure, locally covering on the first bonding pad and an end portion of the bonding wire on the first bonding pad.
14. The package structure as recited in claim 13, wherein the bonding pad contains aluminum.
15. The package structure as recited in claim 13, wherein the sealant structure comprises a glob top structure.
16. A method for packaging micro-electro-mechanical-system (MEMS) microphone, comprising:
- providing a circuit board, a MEMS microphone chip and a circuit chip, wherein the MEMS microphone chip comprises a first bonding pad, the circuit chip comprises a second bonding pad, the first bonding pad comprises: a metal pad on a top of the MEMS microphone chip; and a protection layer fully enclosing a sidewall of the metal pad and also partially disposed on a top of the metal pad;
- disposing the MEMS microphone chip and the circuit chip on the circuit board; and
- performing a bonding process to connect between the first bonding pad and the second bonding pad by a bonding wire.
17. The method for packaging MEMS microphone in claim 16, wherein the metal pad contains aluminum and the protection layer contains TiN.
18. The method for packaging MEMS microphone in claim 16, wherein the protection layer provides a barrier capability from corrosion of the metal pad.
19. The method for packaging MEMS microphone in claim 16, wherein an end portion of the bonding wire in the bonding process is disposed on the top of the metal pad and the protection layer comprises a conductive layer at least covering on the top of the metal pad enclosing the end portion of the bonding wire.
20. The method for packaging MEMS microphone in claim 16, wherein the MEMS microphone chip is provided by:
- forming the metal pad on the top of the MEMS microphone chip;
- forming a conductive layer, covering on the MEMS microphone chip and the metal pad; and
- removing a side portion of the conductive layer, wherein a residual portion of the conductive layer serves as the protection layer to fully cover the top and a sidewall of the metal pad,
- wherein an end portion of the bonding wire in the bonding process is penetrating the protection layer and connected to the metal pad.
21. The method for packaging MEMS microphone in claim 16, wherein the MEMS microphone chip is provided by:
- sequentially forming a metal layer and a conductive layer on the MEMS microphone chip;
- patterning the metal layer and the conductive layer to respectively form the metal pad and a conductive protection layer;
- forming a dielectric layer, fully covering over the metal pad and the protection layer; and
- patterning the dielectric layer to have an opening to expose the conductive protection layer,
- wherein an end portion of the bonding wire in the bonding process within the opening is penetrating the conductive protection layer and connected to the metal pad,
- wherein the dielectric layer with the conductive protection layer forms the protection layer on the metal pad.
22. The method for packaging MEMS microphone in claim 16, wherein the conductive layer comprises a single-layer conductive layer or a conductive layer with a glue layer on the metal pad.
104779213 | July 2015 | CN |
205566635 | September 2016 | CN |
Type: Grant
Filed: Jun 20, 2019
Date of Patent: Nov 17, 2020
Assignee: Solid State System Co., Ltd. (Hsinchu)
Inventors: Chien-Hsing Lee (Hsinchu County), Tsung-Min Hsieh (New Taipei), Cheng-Wei Tsai (Taichung)
Primary Examiner: Phylesha Dabney
Application Number: 16/446,646
International Classification: H04R 25/00 (20060101); H04R 19/04 (20060101); H04R 31/00 (20060101); H04R 1/04 (20060101);